Air pollution control apparatus and air pollution control method

ABSTRACT

An air pollution control apparatus according to an embodiment of the present invention includes: a stack that discharges flue gas discharged from a boiler outside; a blower that is provided downstream of the stack and draws in the flue gas; and a CO 2  recovering apparatus that recovers CO 2  in the flue gas drawn in by the blower. The stack includes a controlling unit that suppresses release of the flue gas outside from the stack and suppresses inflow of atmosphere to the stack, and the controlling unit is a channel forming unit that forms a serpentine channel through which the flue gas and the atmosphere in the stack flow.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an air pollution control apparatus andan air pollution control method that suppress discharge, to theatmosphere, of flue gas discharged from a boiler and the like.

2. Description of the Related Art

Recently, the greenhouse effect of CO₂ has been pointed out as a causeof global warming, and a countermeasure against it has become aninternational urgent task for protecting the global environment. Thesource of CO₂ ranges over every kind of human activities involvingburning of fossil fuels, and the trend is toward further demand for thesuppression of CO₂ discharge. Along with the trend, a method of bringingburnt flue gas from a boiler into contact with amine CO₂ absorbingsolution and reducing and recovering CO₂ in the burnt flue gas, and amethod of preserving recovered CO₂ without releasing it to theatmosphere have been strenuously studied for use at a power generatingfacility such as a thermal power plant that uses a large amount offossil fuels (see, for example, Japanese Patent Application Laid-openNo. 2008-62165).

However, no conventional techniques draw the total amount of flue gasfrom a boiler, a gas turbine, or the like to be discharged from a stackto the atmosphere into a CO₂ recovering apparatus. In recovering CO₂, ithave been demanded to maximize an amount of flue gas drawn in, and notto draw in the atmosphere.

For example, while a fuel gas desulfurization apparatus is generallyprovided downstream of a boiler for reducing sulfur oxide in flue gasdischarged from the boiler, it is proposed to provide a damper or thelike that can be opened and closed as a blocking unit in a stackprovided upstream of the fuel gas desulfurization apparatus. A schematicof a configuration of a conventional fuel gas treatment facility isshown in FIG. 9. As shown in FIG. 9, in this conventional fuel gastreatment facility 100 in which a desulfurization apparatus is installedas an air pollution control apparatus together with a boiler, the totalamount of flue gas 12 discharged from a boiler 11 that is a burningdevice in, for example, a thermal power plant, is drawn by a blower 13,and SO_(x) in the flue gas 12 is reduced for example by a fuel gasdesulfurization apparatus 14. A discharge opening is blocked byproviding a damper 16 or the like that can be opened and closed as ablocking unit in a stack 15 so that sulfur oxide is not discharged tothe atmosphere. The damper 16 is closed when the fuel gasdesulfurization apparatus 14 is operated, and the damper 16 is openedwhen a flue gas source is running, while the operation performed by thefuel gas desulfurization apparatus 14 is stopped.

However, as shown in FIG. 9, when a blocking unit such as the damper 16that can be opened and closed is provided in the stack 15, an industrialfacility (a gas turbine or the like) provided upstream such as theboiler 11 and a turbine is adversely influenced when the damper 16 isclosed while the facility provided upstream such as the boiler 11 and agas turbine is being operated.

Furthermore, when a blocking unit such as the damper 16 is not provided,as shown in FIG. 10, when the operation performed by the CO₂ recoveringapparatus, the fuel gas desulfurization apparatus 14, or the like isstopped for example, and the flow rate of flue gas in the stack 15becomes low, the flue gas 12 having high temperature flows out from acentral portion of the inside of the stack 15, and the atmosphere 17flows in along the inner wall of the stack 15. Thus, the atmosphere 17flows into the stack 15.

In the case of the stack 15 having a short height, and the stack 15having a large inner diameter, the flue gas 12 is more prone to flow outfrom the stack 15, and the atmosphere 17 is more prone to flow into thestack 15.

Accordingly, an appearance of an apparatus has been desired that drawsthe almost total amount of a large amount of flue gas into a CO₂recovering apparatus, and does not discharge the flue gas to theatmosphere safely and stably even when the operation performed by theCO₂ recovering apparatus, the fuel gas desulfurization apparatus, or thelike is stopped for example, with a simple structure without providing ablocking unit such as a damper in the stack.

In view of the problems, an object of the present invention is toprovide an air pollution control apparatus and an air pollution controlsmethod that can draw, into a CO₂ recovering apparatus, almost all amountof flue gas discharged from a stack to the atmosphere stably and safely,and minimizes draw-in of the atmosphere with a simple structure.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, an air pollutioncontrol apparatus includes: a stack that discharges flue gas, dischargedfrom an industrial facility, outside; a blower that is provideddownstream of the stack and draws in the flue gas; and a CO₂ recoveringapparatus that recovers CO₂ in the flue gas drawn in by the blower. Thestack includes a controlling unit that suppresses release of the fluegas outside from the stack and suppresses inflow of atmosphere to thestack, and the controlling unit is a channel forming unit that forms aserpentine channel through which the flue gas and the atmosphere in thestack flow.

Advantageously, in the air pollution control apparatus, the channelforming unit includes: a partition including a portion defining anopening formed at a central portion of the stack in a cross-sectionaldirection in a longitudinal direction and a projection that projects toa tower head of the stack; and a hood-like cover provided to face thepartition with a given gap therebetween.

Advantageously, in the air pollution control apparatus, the channelforming unit includes: an upper flue gas guiding unit extending from awall surface of the stack on a side in which the flue gas flows whenviewed from a cross-sectional direction of a longitudinal direction ofthe stack, and including, at a leading end thereof, a first projectionthat projects downward; and a lower flue gas guiding unit extending froma wall surface of the stack on a side from which the flue gas isdischarged, and including, at a leading end thereof, a second projectionthat projects upward, and the second projection of the lower flue gasguiding unit is provided between the wall surface of the stack and thefirst projection of the upper flue gas guiding unit so that a channelfor the flue gas is formed in the stack.

Advantageously, in the air pollution control apparatus, the channelforming unit includes: a first dam provided at an upper portion of aflue gas channel through which the flue gas is fed from the industrialfacility to the stack when viewed from a cross-sectional direction in alongitudinal direction of the stack; a second dam provided at a lowerportion of an inlet of the stack through which the flue gas is fed tothe stack; and a flue gas guiding unit extending from a wall surface ofthe stack on which the inlet is formed, and including, at a leading endthereof, a projection that projects downward.

According to another aspect of the present invention, an air pollutioncontrol apparatus includes: a stack that discharges flue gas, dischargedfrom an industrial facility, outside; a blower that is provideddownstream of the stack and draws in the flue gas; and a CO₂ recoveringapparatus that recovers CO₂ in the flue gas drawn in by the blower. Thestack includes a controlling unit that suppresses release of the fluegas outside from the stack and suppresses inflow of atmosphere to thestack, and the controlling unit is a mixing unit that mixes the flue gasand the atmosphere.

Advantageously, the air pollution control apparatus further includes aflue gas return flow channel that returns, into the stack, a part of theflue gas fed to the CO₂ recovering apparatus by the blower.

According to still another aspect of the present invention, an airpollution control apparatus includes: a stack that discharges flue gas,discharged from an industrial facility, outside; a blower that isprovided downstream of the stack and draws in the flue gas; and a CO₂recovering apparatus that recovers CO₂ in the flue gas drawn in by theblower. The stack includes a controlling unit that suppresses release ofthe flue gas outside from the stack and suppresses inflow of atmosphereto the stack, and the controlling unit is a leak suppressing unit thatsuppresses inflow of the atmosphere to the stack.

Advantageously, in the air pollution control apparatus, the leaksuppressing unit is at least one resistive part that is provided on awall surface of the stack, and extends toward an exit of the stack whenviewed from a cross-sectional direction in a longitudinal direction ofthe stack.

According to still another aspect of the present invention, an airpollution control apparatus includes: a stack that discharges flue gas,discharged from an industrial facility, outside; a blower that isprovided downstream of the stack and draws in the flue gas; and a CO₂recovering apparatus that recovers CO₂ in the flue gas drawn in by theblower. The stack includes a controlling unit that suppresses release ofthe flue gas outside from the stack and suppresses inflow of atmosphereto the stack, and the controlling unit is an opening/closing unit thatis provided at an inlet of the stack through which the flue gas is fedinto the stack and that is openable only inward of the stack.

According to still another aspect of the present invention, an airpollution control method including using a density difference betweenflue gas discharged from an industrial facility and atmosphere flowingin from outside of a stack, the density difference being caused by atemperature difference therebetween, to prevent the flue gas fromflowing outside.

According to still another aspect of the present invention, an airpollution control method includes mixing flue gas discharged from anindustrial facility and atmosphere flowing in from outside of a stack toprevent the atmosphere from flowing further inside of the stack.

According to still another aspect of the present invention, an airpollution control method using the air pollution control apparatusdescribed above to prevent the flue gas from flowing outside of thestack.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of a configuration of an air pollution controlapparatus according to a first embodiment of the present invention;

FIG. 2 is a partially enlarged schematic of a configuration of theinside of a stack;

FIG. 3 is a schematic of a configuration of an air pollution controlapparatus according to a second embodiment of the present invention;

FIG. 4 is a schematic of a configuration of an air pollution controlapparatus according to a third embodiment of the present invention;

FIG. 5 is a schematic of a configuration of an air pollution controlapparatus according to a fourth embodiment of the present invention;

FIG. 6 is a schematic of another configuration of the air pollutioncontrol apparatus according to the fourth embodiment of the presentinvention;

FIG. 7 is a schematic of a configuration of an air pollution controlapparatus according to a fifth embodiment of the present invention;

FIG. 8 is a schematic of a configuration of an air pollution controlapparatus according to a sixth embodiment of the present invention;

FIG. 9 is a schematic of an exemplary configuration of a conventionalfuel gas treatment facility; and

FIG. 10 is a schematic of flow of flue gas and atmosphere in a stack.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Exemplary embodiments of the present invention are explained in detailwith reference to the figures. The present invention is not limited bythe embodiments. Components in the embodiments include those that can beconceived of easily by a person skilled in the art, those that aresubstantially the same, and those that are equivalent to the components.

First Embodiment

An air pollution control apparatus according to an embodiment of thepresent invention is explained with reference to FIG. 1.

FIG. 1 is a schematic of a configuration of this air pollution controlapparatus according to a first embodiment of the present invention. FIG.2 is a partially enlarged schematic of a configuration of the inside ofa stack. In FIGS. 1 and 2, components that are the same as theircounterparts shown in FIG. 9 are provided with the same symbols, and arenot explained repeatedly.

As shown in FIG. 1, a first air pollution control apparatus 10Aaccording to the first embodiment of the present invention includes: astack 15 that discharges, to the outside, flue gas 12 discharged from aboiler 21, a gas turbine, or the like provided in an industrialfacility; a blower 13 that is provided downstream of the stack 15, anddraws in the flue gas 12; and a CO₂ recovering apparatus 22 thatrecovers CO₂ in the flue gas 12 drawn in by the blower 13. The first airpollution control apparatus 10A additionally includes, in the stack 15,a controlling unit that suppresses release of the flue gas 12 from thestack 15 to the outside, and suppresses inflow of atmosphere 17 to thestack 15. As the controlling unit, a channel forming unit 23A that formsa serpentine channel through which the flue gas 12 and the atmosphere 17flow is provided in the stack 15.

The flue gas 12 containing CO₂ discharged from the boiler 21, the gasturbine, or the like provided in an industrial facility is fed to thestack 15 through a flue gas channel 24 through which the flue gas 12 isfed from the boiler 21 to the stack 15, is pressurized by the blower 13,is discharged from the stack 15, and is fed to the CO₂ recoveringapparatus 22 through the flue gas discharge channel 25.

In the present embodiment, the channel forming unit 23A used as thecontrolling unit includes a partition 28 including an opening 26 formedat a central portion of the stack 15 in the cross-sectional direction inthe longitudinal direction, and a projection 27 that projects to a towerhead 15 a of the stack 15, and a hood-like cover 29 provided to face thepartition 28 with a given gap therebetween.

When the operation performed by an apparatus such as the boiler 21 andthe CO₂ recovering apparatus 22 is stopped for example, the flue gas 12that has flowed into the stack 15 is partly fed to the CO₂ recoveringapparatus 22 through the flue gas discharge channel 25, while the restascends the stack 15, passes the opening 26 of the partition 28 formedby the projection 27, and reaches a space A in the cover 29. Meanwhile,the atmosphere 17 that has flowed in to the stack 15 from the outside isfed to a space B formed by an inner wall 15 b of the stack 15, theprojection 27, and the partition 28. The temperature of the flue gas 12is about 100 to 180° C., and the temperature of the atmosphere 17 isabout 0 to 30° C. Because the temperature of the flue gas 12 is higherthan the temperature of the atmosphere 17, the density of the flue gas12 is smaller than the density of the atmosphere 17. Accordingly, whenthe flue gas 12 and the atmosphere 17 come into contact with each other,the flue gas 12 becomes buoyant, and stays higher than the atmosphere17, and as shown in FIG. 2, a boundary region X is formed between theflue gas 12 and the atmosphere 17 due to the interaction of thetemperature difference and the density difference between the flue gas12 and the atmosphere 17.

Accordingly, due to the density difference of the flue gas 12 and theatmosphere 17 generated by the temperature difference of the flue gas 12and the atmosphere 17, the atmosphere 17 that has flowed into the spaceB prevents the flue gas 12 fed to the space A from traveling. Thus, theflue gas 12 can be kept in the space A. The flue gas 12 that has flowedinto the space A also prevents the atmosphere 17 that has flowed intothe space B from traveling. Thus, the atmosphere 17 can be kept in thespace B. Because the flue gas 12 fed into the stack 15 is sealed by theatmosphere 17 at the boundary region X between the flue gas 12 and theatmosphere 17 formed by the interaction of the temperature differenceand the density difference between the flue gas 12 and the atmosphere17, the flue gas 12 can be prevented from being discharged to theoutside of the stack 15. Accordingly, when the operation performed bythe CO₂ recovering apparatus 22 or the like is stopped for example, theatmosphere 17 can be prevented from flowing into the stack 15 withoutcontrolling opening and closing of the stack by providing a blockingunit such as a damper as in the conventional technique.

Therefore, in the first air pollution control apparatus 10A according tothe first embodiment, even when the operation performed by an apparatussuch as the CO₂ recovering apparatus 22 is stopped for example, thealmost total amount of the flue gas 12 otherwise discharged from thestack 15 to the outside can be drawn into the CO₂ recovering apparatus22 stably and safely with a simple structure, and draw-in of theatmosphere 17 to the CO₂ recovering apparatus 22 or the like can besuppressed.

Accordingly, CO₂ recovery rate of the CO₂ recovering apparatus 22 can beincreased safely at any time without an adverse influence on an upstreamfacility, and CO₂ recovery performance of the CO₂ recovering apparatus22 can be kept high because CO₂ in the flue gas 12 is not diluted by theatmosphere 17. Because the stack 15, a duct, or the like is not cooledby draw-in of the atmosphere 17 to the CO₂ recovering apparatus 22 orthe like, generation of corrosion can be suppressed. Furthermore, adamage to an industrial facility such as the boiler 21 and a gas turbineprovided upstream of the stack 15 can be prevented.

Second Embodiment

FIG. 3 is a schematic of a configuration of an air pollution controlapparatus according to a second embodiment of the present invention. Theair pollution control apparatus according to the present embodiment isexplained with reference to FIG. 3. Components that are the same as thecounterparts in the air pollution control apparatus according to thefirst embodiment are provided with the same symbols, and are notexplained repeatedly.

In this second air pollution control apparatus 10B according to thepresent embodiment, a channel forming unit 23B used as a controllingunit includes: an upper flue gas guiding unit 32 extending from the wallsurface 15 b of the stack 15 on the side in which the flue gas 12 flowswhen viewed from the cross-sectional direction in the longitudinaldirection of the stack 15 and including, at its leading end, a firstprojection 31 that projects downward; and a lower flue gas guiding unit34 extending from the inner wall 15 b of the stack 15 on the side inwhich the flue gas 12 flows and including, at its leading end, a secondprojection 33 that projects upward. The second projection 33 of thelower flue gas guiding unit 34 is provided between the inner wall 15 bof the stack 15 and the first projection 31 of the upper flue gasguiding unit 32, so that a channel for the flue gas 12 is formed in thestack 15.

The flue gas 12 discharged from the boiler 21 and fed to the flue gaschannel 24 passes through the stack 15, and is fed to the CO₂ recoveringapparatus 22 through the flue gas discharge channel 25. When theoperation performed by an apparatus such as the boiler 21 and the CO₂recovering apparatus 22 is stopped for example, the flue gas 12 that hasflowed into the stack 15 is partly fed to the CO₂ recovering apparatus22 through the flue gas discharge channel 25, while the rest ascends thespace formed by the inner wall 15 b and the second projection 33, and isfed to a space C formed by the inner wall 15 b, the upper flue gasguiding unit 32, and the first projection 31. Meanwhile, the atmosphere17 that has flowed into the stack 15 descends the space formed by theinner wall 15 b and the first projection 31, and is fed to a space Dformed by the inner wall 15 b, the lower flue gas guiding unit 34, andthe second projection 33.

Because the temperature of the flue gas 12 is higher than thetemperature of the atmosphere 17, when the flue gas 12 in the space Cand the atmosphere 17 in the space D come into contact with each other,the flue gas 12 becomes buoyant due to the density difference betweenthe flue gas 12 and the atmosphere 17 caused by the temperaturedifference between the flue gas 12 and the atmosphere 17, and stayshigher than the atmosphere 17. The boundary region X between the fluegas 12 and the atmosphere 17 is formed by the interaction of thetemperature difference and the density difference between the flue gas12 and the atmosphere 17. Accordingly, the atmosphere 17 in the space Dprevents the flue gas 12 in the space C from traveling. Thus, the fluegas 12 can be kept in the space C. Meanwhile, because the flue gas 12kept in the space C prevents the atmosphere 17 from traveling, theatmosphere 17 can be kept in the space D.

Accordingly, because the flue gas 12 that has flowed into the stack 15is sealed by the atmosphere 17 at the boundary X formed by the flue gas12 and the atmosphere 17 due to the interaction of the temperaturedifference and the density difference between the flue gas 12 and theatmosphere 17, the flue gas 12 can be prevented from being discharged tothe outside of the stack 15.

Although, in the air pollution control apparatus 10B according to thepresent embodiment, only the channel forming unit 23B is provided in thechannel 15 as a channel forming unit, the present invention is notlimited to this configuration, and the channel forming unit 23A of thefirst air pollution control apparatus 10A according to the firstembodiment shown in FIG. 1 may be used in combination.

Third Embodiment

FIG. 4 is a schematic of a configuration of an air pollution controlapparatus according to a third embodiment of the present invention. Theair pollution control apparatus according to the present embodiment isexplained with reference to FIG. 4. Components that are the same as thecounterparts in the air pollution control apparatus according to thefirst embodiment are provided with the same symbols, and are notexplained repeatedly.

In this third air pollution control apparatus 10C according to thepresent embodiment, a channel forming unit 23C used as a controllingunit includes a first dam 35 provided at the upper portion of the fluegas channel 24 through which the flue gas 12 is fed from the boiler 21to the stack 15 when viewed from the cross-sectional direction in thelongitudinal direction of the stack 15, a second dam 37 provided at thelower portion of an inlet 36 of the stack 15 through which the flue gas12 is fed to the stack 15, and a flue gas guiding unit 39 extending fromthe inner wall 15 b of the stack 15 on the side on which the inlet 36 isformed, and including, at its leading end, a projection 38 that projectsdownward.

The flue gas 12 discharged from the boiler 21 is fed into a space Eformed by the first dam 35, the flue gas guiding unit 39, and theprojection 38, and is fed to the CO₂ recovering apparatus 22 through theflue gas discharge channel 25. When the operation performed by anapparatus such as the boiler 21 and the CO₂ recovering apparatus 22 isstopped for example, the flue gas 12 fed from the flue gas channel 24 isfed to the space E. Meanwhile, the atmosphere 17 flows into the stack15, descends the space formed by the inner wall 15 b and the projection38, and is fed to a space F formed by the inner wall 15 b, the seconddam 37, and a bottom 15 c of the stack 15.

Because the temperature of the flue gas 12 fed from the flue gas channel24 is higher than the temperature of the atmosphere 17, when the fluegas 12 in the space E and the atmosphere 17 in the space F come intocontact with each other, the flue gas 12 stays higher than theatmosphere 17 due to the density difference between flue gas 12 and theatmosphere 17 caused by the temperature difference between the flue gas12 and the atmosphere 17. The boundary region X between the flue gas 12and the atmosphere 17 is formed by the interaction of the temperaturedifference and the density difference between the flue gas 12 and theatmosphere 17.

Accordingly, because the atmosphere 17 in the space F prevents the fluegas 12 in the space E from traveling, the flue gas 12 can be kept in thespace E, and because the flue gas 12 kept in the space E prevents theatmosphere 17 from traveling, the atmosphere 17 can be kept in the spaceF. Therefore, because the flue gas 12 fed into the stack 15 is sealed bythe atmosphere 17 in the space F at the boundary region X between theflue gas 12 and the atmosphere 17 formed by the interaction of thetemperature difference and the density difference between the flue gas12 and the atmosphere 17, the flue gas 12 can be prevented from beingdischarged to the outside of the stack 15.

Alternatively, a flue gas branch channel 40 through which the flue gas12 is fed to the CO₂ recovering apparatus 22 may be provided in the fluegas channel 24. When the operation performed by the boiler 21, aturbine, or the like provided in an industrial facility is stopped, theflue gas 12 remaining in the flue gas channel 24 and the flue gas 12 inthe space E can be led out of the flue gas branch channel 40, and fed tothe CO₂ recovering apparatus 22.

Although, in the third air pollution control apparatus 10C according tothe present embodiment, the first dam 35 is provided at the upperportion of the flue gas channel 24, the dam 35 may not be providedbecause it is necessary only to keep the flue gas 12 in the region ofthe space E formed by the projection 38 and the flue gas guiding unit 39and make the flue gas 12 stay higher than the atmosphere 17 to seal theflue gas 12.

Although in the third air pollution control apparatus 10C according tothe present embodiment, only the channel forming unit 23C is provided inthe stack 15 as a channel forming unit, the present invention is notlimited to this configuration, and any one of the channel forming unit23A of the first air pollution control apparatus 10A according to thefirst embodiment shown in FIG. 1, and the channel forming unit 23B ofthe second air pollution control apparatus 10B according to the secondembodiment shown in FIG. 3 or both may be used in combination.

Fourth Embodiment

FIG. 5 is a schematic of a configuration of an air pollution controlapparatus according to a fourth embodiment of the present invention. Theair pollution control apparatus according to the present embodiment isexplained with reference to FIG. 5. Components that are the same as thecounterparts in the air pollution control apparatus according to thefirst embodiment are provided with the same symbols, and are notexplained repeatedly.

This fourth air pollution control apparatus 10D according to the presentembodiment uses a static mixer (a mixing unit) 41 as a controlling unitthat mixes the flue gas 12 and the atmosphere 17. By providing thestatic mixer 41 in the stack 15, the flue gas 12 and the atmosphere 17are mixed by the static mixer 41 when the atmosphere 17 flows into thestack 15, thereby stopping the flow of the flue gas 12 and theatmosphere 17. Thus, inflow of the atmosphere 17 to the stack 15 can bedecreased. Furthermore, the flue gas 12 or the atmosphere 17 can beprevented from being discharged solely from the stack 15. Even when theoperation performed by an apparatus such as the CO₂ recovering apparatus22 is stopped for example, inflow of the atmosphere 17 to the stack 15can be decreased, the almost total amount of the flue gas 12 otherwisedischarged from the stack 15 to the outside can be drawn into the CO₂recovering apparatus 22 stably and safely with a simple structure, anddraw-in of the atmosphere 17 to the CO₂ recovering apparatus 22 or thelike can be suppressed.

Alternatively, in the fourth air pollution control apparatus 10Daccording to the present embodiment, a flue gas return flow channel 42that returns, into the stack 15, a part of the flue gas 12 fed by theblower 13 to the CO₂ recovering apparatus 22 may be provided as shown inFIG. 6. By returning a part of the flue gas 12 into the stack 15 throughthe flue gas return flow channel 42, the atmosphere 17 is less prone toflow into the stack 15 from the outside of the stack 15. Thus, inflow ofthe atmosphere 17 to the stack 15 can be further decreased.

Although a spiral member like the static mixer 41 is used as a mixingunit in the fourth air pollution control apparatus 10D according to thepresent embodiment, the present invention is not limited to theconfiguration, and any spiral member that can mix the flue gas 12 andthe atmosphere 17 may be used. Alternatively, any non-spiral member thatcan mix the flue gas 12 and the atmosphere 17 may be used.

Although only the static mixer 41 is provided in the stack 15 as amixing unit in the fourth air pollution control apparatus 10D accordingto the present embodiment, the present invention is not limited to theconfiguration, and at least any one of the channel forming unit 23A ofthe first air pollution control apparatus 10A according to the firstembodiment shown in FIG. 1, the channel forming unit 23B of the secondair pollution control apparatus 10B according to the second embodimentshown in FIG. 3, and the channel forming unit 23C of the third airpollution control apparatus 100 according to the third embodiment shownin FIG. 4 may be used in combination.

Fifth Embodiment

FIG. 7 is a schematic of a configuration of an air pollution controlapparatus according to a fifth embodiment of the present invention. Theair pollution control apparatus according to the present embodiment isexplained with reference to FIG. 7. Components that are the same as thecounterparts in the air pollution control apparatus according to thefirst embodiment are provided with the same symbols, and are notexplained repeatedly.

This fifth air pollution control apparatus 10E according to the presentembodiment uses a leak suppressing unit as a controlling unit thatsuppresses inflow of the atmosphere 17 to the stack 15. In the presentembodiment, three resistive parts 51 extending to the exit of the stack15 when viewed from the cross-sectional direction in the longitudinaldirection of the stack 15 are provided as the leak suppressing unit atthe inner wall 15 b of the stack 15. The resistive parts 51 are providedalong the inner wall 15 b of the stack 15.

Because the temperature of the atmosphere 17 is lower than thetemperature of the flue gas 12, the flow rate of the atmosphere 17 thathas flowed into the stack 15 descending along the inner wall of thestack 15 is larger than the flow rate of the atmosphere 17 descending atthe central portion of the stack 15. Accordingly, by providing theresistive parts 51 at the inner wall 15 b of the stack 15, the inflowrate of the atmosphere 17 descending along the inner wall of the stack15 can be suppressed. Furthermore, inflow of the atmosphere 17descending at the central portion of the stack 15 to the stack 15 can bedecreased due to the flue gas 12 fed into the stack 15 and ascending thestack 15. Even when the operation performed by an apparatus such as theCO₂ recovering apparatus 22 is stopped for example, the inflow rate ofthe atmosphere 17 to the stack 15 can be decreased, the almost totalamount of the flue gas 12 otherwise discharged from the stack 15 to theoutside can be drawn into the CO₂ recovering apparatus 22 stably andsafely with a simple structure, and draw-in of the atmosphere 17 to theCO₂ recovering apparatus 22 or the like can be suppressed.

Although the number of the resistive parts 51 provided are three in thefifth air pollution control apparatus 10E according to the presentembodiment, the number of the resistive parts 51 may be changedappropriately according to the suppression rate of the atmosphere 17.

Although the resistive part extending to the exit of the stack 15 whenviewed from the cross-sectional direction in the longitudinal directionof the stack 15 is employed in the fifth air pollution control apparatus10E according to the present embodiment, the present invention is notlimited to this configuration, and any member that can suppress inflowof the atmosphere 17 to the stack 15 may be employed.

Further, although only the leak suppressing unit for suppressing inflowof the atmosphere 17 to the stack 15 is provided in the stack 15 as acontrolling unit in the fifth air pollution control apparatus 10Eaccording to the present embodiment, the present invention is notlimited to this configuration. For example, at least any one of thechannel forming unit 23A of the first air pollution control apparatus10A according to the first embodiment shown in FIG. 1, the channelforming unit 23B of the second air pollution control apparatus 10Baccording to the second embodiment shown in FIG. 3, the channel formingunit 23C of the third air pollution control apparatus 10C according tothe third embodiment shown in FIG. 4, and the mixing unit 41 of thefourth air pollution control apparatus 10D according to the fourthembodiment shown in FIG. 5 may be used in combination.

Sixth Embodiment

FIG. 8 is a schematic of a configuration of an air pollution controlapparatus according to a sixth embodiment of the present invention. Theair pollution control apparatus according to the present embodiment isexplained with reference to FIG. 8. Components that are the same as thecounterparts in the air pollution control apparatus according to thefirst embodiment are provided with the same symbols, and are notexplained repeatedly.

A sixth air pollution control apparatus 10F according to the presentembodiment uses a dumper (an opening/closing unit) 52 as a controllingunit that is provided at the inlet 36 of the stack 15 through which theflue gas 12 is fed into the stack 15 and that can be opened only inwardof the stack 15.

The dumper 52 is openable only inward of the stack 15 about one end ofthe inlet 36. Accordingly, by providing the dumper 52 at the inlet 36 ofthe inner wall 15 b, when the CO₂ recovering apparatus 22 is running andthe blower 13 is drawing in the flue gas 12, or when an industrialfacility such as the boiler 21 and a gas turbine is running and thepressure in the flue gas channel 24 is positive, the dumper 52 that isopenable only inward of the stack 15 can be kept open inward of thestack 15 so that the flue gas 12 can be drawn into the CO₂ recoveringapparatus 22.

When the operation performed by an industrial facility such as theboiler 21 and a gas turbine positioned upstream of the stack 15, and theCO₂ recovering apparatus 22 is stopped for example, the inlet 36 can beclosed with the damper 52. Thus, the atmosphere 17 can be prevented fromflowing into an industrial facility such as the boiler 21 and a gasturbine.

Alternatively, the flue gas branch channel 40 through which the flue gas12 is fed to the CO₂ recovering apparatus 22 may be provided in the fluegas channel 24. When the operation performed by an industrial facilitysuch as the boiler 21 and a gas turbine is stopped, while the CO₂recovering apparatus 22 is running, the flue gas 12 remaining in theflue gas channel 24 may be led out of the flue gas branch channel 40,and fed to the CO₂ recovering apparatus 22. When an industrial facilitysuch as the boiler 21 and a gas turbine is running while an apparatussuch as the CO₂ recovering apparatus 22 is not operated, the flue gas 12in the flue gas channel 24 may be led out of the flue gas branch channel40, and when the CO₂ recovering apparatus 22 starts running, the fluegas 12 may be fed to the CO₂ recovering apparatus 22. When the operationperformed by an industrial facility such as the boiler 21 and a gasturbine, and the CO₂ recovering apparatus 22 is stopped, the flue gas 12may be led out of the flue gas branch channel 40, and fed to the CO₂recovering apparatus 22 when the CO₂ recovering apparatus 22 startsrunning.

Although, in the sixth air pollution control apparatus 10F according tothe present embodiment, only the dumper 52 openable only inward of thestack 15 is provided as a opening/closing unit at the inlet 36 of thestack 15, the present invention is not limited to this configuration.For example, at least any one of the channel forming unit 23A of thefirst air pollution control apparatus 10A according to the firstembodiment shown in FIG. 1, the channel forming unit 10B of the secondair pollution control apparatus 23B according to the second embodimentshown in FIG. 3, the channel forming unit 23C of the third air pollutioncontrol apparatus 10C according to the third embodiment shown in FIG. 4,the mixing unit 41 of the fourth air pollution control apparatus 10Daccording to the fourth embodiment shown in FIG. 5, and the resistivepart 51 of the fifth air pollution control apparatus 10E according tothe fifth embodiment shown in FIG. 7 may be used in combination.

Although the present invention is explained as being used in an airpollution control apparatus including the CO₂ recovering apparatus 22,it may be used in an air pollution control apparatus including anotherapparatus such as a fuel gas desulfurization apparatus other than theCO₂ recovering apparatus 22.

According to an air pollution control apparatus of an embodiment of thepresent invention, without a blocking unit such as a damper, a stackincludes a controlling unit that suppresses release of the flue gasoutside from the stack and suppresses inflow of atmosphere to the stack,and the controlling unit is a channel forming unit that forms aserpentine channel through which the flue gas and the atmosphere in thestack flow. Even when the operation performed by an apparatus such asthe CO₂ recovering apparatus is stopped for example, inflow of theatmosphere to the stack can be decreased, almost all amount of the fluegas discharged from the stack to the outside can be drawn into the CO₂recovering apparatus stably and safely with a simple structure, anddraw-in of the atmosphere to the CO₂ recovering apparatus or the likecan be suppressed.

According to an air pollution control apparatus of an embodiment of thepresent invention, a stack includes a controlling unit that suppressesrelease of the flue gas outside from the stack and suppresses inflow ofatmosphere to the stack, and the controlling unit is a mixing unit thatmixes the flue gas and the atmosphere. Therefore, even when a devicesuch as the CO₂ recovering apparatus stops running, inflow of theatmosphere into the stack is reduced. Almost all of the flue gasdischarged from the stack is draw to the CO₂ recovering apparatus sidestably and safely by a simple configuration of the apparatus. Also, adrawn-in of the atmosphere to the CO₂ recovering apparatus issuppressed.

According to an air pollution control apparatus of an embodiment of thepresent invention, a stack includes a controlling unit that suppressesrelease of the flue gas outside from the stack and suppresses inflow ofatmosphere to the stack, and the controlling unit is a leak suppressingunit that suppresses inflow of the atmosphere to the stack. Therefore,even when a device such as the CO₂ recovering apparatus stops running,inflow of the atmosphere into the stack is reduced. Almost all of theflue gas discharged from the stack is draw to the CO₂ recoveringapparatus side stably and safely by a simple configuration of theapparatus. Also, a drawn-in of the atmosphere to the CO₂ recoveringapparatus is suppressed.

According to an air pollution control apparatus of an embodiment of thepresent invention, a stack includes a controlling unit that suppressesrelease of the flue gas outside from the stack and suppresses inflow ofatmosphere to the stack, and the controlling unit is an opening/closingunit that is provided at an inlet of the stack through which the fluegas is fed into the stack and that is openable only inward of the stack.Therefore, when the CO₂ recovering apparatus is running, and the bloweris drawing in the flue gas, and when an industrial facility such as aboiler and a gas turbine is running, and the pressure in the flue gaschannel is positive, the opening/closing unit can be kept open inward ofa stack. Thus, the flue gas can be drawn into the CO₂ recoveringapparatus. When the operation performed by an apparatus such as the CO₂recovering apparatus is stopped for example, the inlet can be closedwith the opening/closing unit. Thus, the atmosphere can be preventedfrom flowing into an industrial facility such as the boiler and a gasturbine.

Although the invention has been described with respect to a specificembodiment for a complete and clear disclosure, the appended claims arenot to be thus limited but are to be construed as embodying allmodifications and alternative constructions that may occur to oneskilled in the art that fairly fall within the basic teaching herein setforth.

1. An air pollution control apparatus comprising: a stack thatdischarges flue gas, discharged from an industrial facility, outside; ablower that is provided downstream of the stack and draws in the fluegas; and a CO₂ recovering apparatus that recovers CO₂ in the flue gasdrawn in by the blower, wherein the stack includes a controlling unitthat suppresses release of the flue gas outside from the stack andsuppresses inflow of atmosphere to the stack, and the controlling unitis a channel forming unit that forms a serpentine channel through whichthe flue gas and the atmosphere in the stack flow.
 2. The air pollutioncontrol apparatus according to claim 1, wherein the channel forming unitincludes: a partition including a portion defining an opening formed ata central portion of the stack in a cross-sectional direction in alongitudinal direction and a projection that projects to a tower head ofthe stack; and a hood-like cover provided to face the partition with agiven gap therebetween.
 3. The air pollution control apparatus accordingto claim 1, wherein the channel forming unit includes: an upper flue gasguiding unit extending from a wall surface of the stack on a side inwhich the flue gas flows when viewed from a cross-sectional direction ofa longitudinal direction of the stack, and including, at a leading endthereof, a first projection that projects downward; and a lower flue gasguiding unit extending from a wall surface of the stack on a side fromwhich the flue gas is discharged, and including, at a leading endthereof, a second projection that projects upward, and the secondprojection of the lower flue gas guiding unit is provided between thewall surface of the stack and the first projection of the upper flue gasguiding unit so that a channel for the flue gas is formed in the stack.4. The air pollution control apparatus according to claim 1, wherein thechannel forming unit includes: a first dam provided at an upper portionof a flue gas channel through which the flue gas is fed from theindustrial facility to the stack when viewed from a cross-sectionaldirection in a longitudinal direction of the stack; a second damprovided at a lower portion of an inlet of the stack through which theflue gas is fed to the stack; and a flue gas guiding unit extending froma wall surface of the stack on which the inlet is formed, and including,at a leading end thereof, a projection that projects downward.
 5. An airpollution control apparatus comprising: a stack that discharges fluegas, discharged from an industrial facility, outside; a blower that isprovided downstream of the stack and draws in the flue gas; and a CO₂recovering apparatus that recovers CO₂ in the flue gas drawn in by theblower, wherein the stack includes a controlling unit that suppressesrelease of the flue gas outside from the stack and suppresses inflow ofatmosphere to the stack, and the controlling unit is a mixing unit thatmixes the flue gas and the atmosphere.
 6. The air pollution controlapparatus according to claim 5, further comprising a flue gas returnflow channel that returns, into the stack, a part of the flue gas fed tothe CO₂ recovering apparatus by the blower.
 7. An air pollution controlapparatus comprising: a stack that discharges flue gas, discharged froman industrial facility, outside; a blower that is provided downstream ofthe stack and draws in the flue gas; and a CO₂ recovering apparatus thatrecovers CO₂ in the flue gas drawn in by the blower, wherein the stackincludes a controlling unit that suppresses release of the flue gasoutside from the stack and suppresses inflow of atmosphere to the stack,and the controlling unit is a leak suppressing unit that suppressesinflow of the atmosphere to the stack.
 8. The air pollution controlapparatus according to claim 7, wherein the leak suppressing unit is atleast one resistive part that is provided on a wall surface of thestack, and extends toward an exit of the stack when viewed from across-sectional direction in a longitudinal direction of the stack. 9.An air pollution control apparatus comprising: a stack that dischargesflue gas, discharged from an industrial facility, outside; a blower thatis provided downstream of the stack and draws in the flue gas; and a CO₂recovering apparatus that recovers CO₂ in the flue gas drawn in by theblower, wherein the stack includes a controlling unit that suppressesrelease of the flue gas outside from the stack and suppresses inflow ofatmosphere to the stack, and the controlling unit is an opening/closingunit that is provided at an inlet of the stack through which the fluegas is fed into the stack and that is openable only inward of the stack.10. An air pollution control method comprising using a densitydifference between flue gas discharged from an industrial facility andatmosphere flowing in from outside of a stack, the density differencebeing caused by a temperature difference therebetween, to prevent theflue gas from flowing outside.
 11. An air pollution control methodcomprising mixing flue gas discharged from an industrial facility andatmosphere flowing in from outside of a stack to prevent the atmospherefrom flowing further inside of the stack.
 12. An air pollution controlmethod using the air pollution control apparatus according to claim 1 toprevent the flue gas from flowing outside of the stack.